Method and device for welding pipes

ABSTRACT

Method for welding piped ( 2, 3 ) to each other, in which the outer side of the one pipe is engaged tightly with the help of first clamping means and the outer side of the other pipe is engaged tightly with the help of second clamping means in which the first and second clamping means are kept in the line and with their ends close to or against each other by means of a rigid frame on which both clamping means are arranged, after which welding means are operated in order to make a welding seam from the outside for connecting both pipes, after which the frame with the first and the second clamping means and with the welding means is moved along and over the other pipe to the other end of the other pipe for repeating the aforementioned steps for welding the other pipe and a next pipe.

This application is a continuation of application Ser. No. 10/138,024filed on May 2, 2002 (now U.S. Pat. No. 6,840,433) which is acontinuation of International Application PCT/NL00/00792 filed on Nov.1, 2000, which designated the U.S., claims the benefit thereof andincorporates the same by reference.

FIELD OF INVENTION

The invention relates to a method and a device for welding pipes ortubes to each other for forming pipe lines for instance oil or gas, inwhich two pipes to be welded to each other are aligned with respect toeach other and then a connecting weld is made. The inventionparticularly relates to welding stationary, lying pipes to each other.

BACKGROUND OF INVENTION

It is known to use a so-called line-up clamp to that end, which clamp ismoved within the pipes until on either side of the weld to be formed,and which, at that location, is brought into clamping engagement withthe inner surfaces of the ends of the pipes to be welded together. Theframe on which the clamping means for both pipes have been arrangedprovides a rigid orienting means, as a result of which the pipes will beexactly aligned before welding. Such an arrangement is for instanceshown in Dutch patent application 90.02396. Here, after orienting thepipes an annular supporting frame for the welding equipment is placed atthe outside of the pipes, using a mounting belt arranged earlier on onone of the pipes. For said technique, International patent applicationWO 95/21721 could also be referred to, in which document a line-up clampwhich is mobile within the pipes is described.

The use of a line-up clamp which moves within the pipes requires specialprovisions, such as long operating lines, the length of whichcorresponds to the length of the pipe line made ready. Furthermore theline-up clamp has to be retrieved entirely in case it malfunctions. Thisresults in considerable delays in the work.

It is an object of the invention to improve on this.

SUMMARY OF INVENTION

From one aspect the invention to that end provides a method for weldingpipes to each other, in which the outer side of the one pipe is engagedtightly with the help of first clamping means and the outer side of theother pipe is engaged tightly with the help of second clamping means, inwhich the first and second clamping means are kept in line and withtheir ends close to or against each other by means of a rigid frame onwhich both clamping means are arranged, after which welding means areoperated in order to make a welding seam from the outside for connectingboth pipes, after which the frame with the first and the second clampingmeans and with the welding means is moved along and over the other pipeto the other end of the other pipe for repeating the aforementionedsteps for welding the other pipe and a next pipe.

By letting the clamping means for the pipes to be welded together engageat the outside they can always be reached well and can be checked. Theoperating lines can remain short here, despite the fact that they haveto make the movement of the frame possible. Moving the frame over thepipes makes it possible to use the pipes as a guide and a support, as aresult of which the frame can be kept simple.

It is noted that from European Patent application 0.119.636 it is knownto use a stationary frame for welding vertical pipes to each other,which frame comprises a cage construction with two coaxial sleeves in itfor accommodation of the two pipe ends, in which at the outside of thesleeves two clamping jaws acting on the sleeves are provided forfixating the pipes in their positions. The frame is furthermore providedwith welding means. After arranging a weld the clamping means aredetached and the upper pipe is pushed downward until said pipe and thepipe placed on it are accommodated in their respective sleeves, afterwhich the process can start over again.

Preferably use is made of rollers on or at the frame for engagement ofthe outer side of the pipes, in which the rollers can be rotated aboutan axis perpendicular to the centre line of the pipes, in which way asimple guiding and supporting means for the frame on the pipes is used.

Preferably the frame is moved over the pipes by means of driving meansprovided on the frame, such as a driven roller for instance. Externalprovisions can be kept limited as a result.

Alternatively it is possible to pull the frame on a cable, in which casethe frame can remain lightweight and the movement can take place morequickly.

Preferably at least a first connecting weld is made between the pipes bymeans of welding means that are supported on the frame. Here the frameis used for other purposes, whereas the frame also ensures movement ofsaid welding means, so that no additional measures need to be taken.

In accordance with one embodiment of the invention, there is provided adevice for welding a plurality of pipes to each other, said devicecomprising (a) a rigid frame (100), (b) first (30, 32) and second (31,33) clamping means supported on the frame for tightly engaging outersides of respective first (2) and second (3) pipes having respectiveends in line with and at a welding distance from each other, each ofsaid first (30, 32) and second (31, 33) clamping means comprising aplurality of circumferentially extending clamping members, (c) movementmeans on the frame for moving the frame along and over the plurality ofpipes while being supported on the pipes, and (d) welding means (80)supported on the frame for welding the plurality of pipes.

In a further development of the method according to the invention, thewelding activities are split up, to which end after making the firstconnecting weld the frame is moved to a next pipe transition, and theweld is finished with the help of external welding means, preferablysimultaneously to the movement or the making of the next firstconnecting weld. The—relatively expensive—line-up part here is used nolonger than strictly necessary and it can be used again quickly for anext welding process. The weld connection is sufficiently strong herefor holding both pipes together. The weld can be finished with simplerwelding means.

From a further aspect the shape of the one pipe is determined with thehelp of the first clamping means, said shape is stored in a memory asshape data, the second clamping means are brought into engagement withthe other pipe and based on the shape data stored in the memory areurged into a position corresponding to the shape stored.

Thus it can be achieved that the contours of the end edges of both pipeshave the same shape, so that the weld can be properly arranged and areliable connection can be laid over the entire circumference. Pipes areusually a little deformed and different as to roundness, which by usingthe method according to the invention need not have detrimental effectsany more, as the shape is now partly adjusted.

It is preferable here that after storing the shape data of the one pipe,the first clamping means are further operated until in a position inwhich the one pipe is clamped.

Preferably the second clamping means are operated to clamp the otherpipe after said deformation movement.

From a further aspect the invention provides the measure that the firstand second clamping means are arranged on two respective frame parts,which are connected to each other in an adjustable manner in pipe axisdirection, in which the mutual axial distance of the end edges of bothpipes is adjusted to the weld shape to be made.

From another aspect the invention provides a device for welding pipes toeach other, comprising a rigid frame having first clamping means fortightly engaging the outer side of the one pipe and having secondclamping means for tightly engaging the outer side of the other pipe,having its end at welding distance from and in line with the end of theone pipe, and having means for moving the frame along and over the pipesafter making the welded joint between the pipes.

Preferably the movement means comprise means for guiding engagement ofthe outer side of the pipes, which are preferably formed by rollers, forrolling support of the frame on the pipes.

Preferably the device according to the invention comprises welding meanssupported on the frame, such as in particular a welding robot guidance,and possibly means for welding gas supply and/or a welding wire supply.The service lines towards the device can be kept short and simple as aresult. This may result in a largely independent combined aligning andwelding device.

Preferably the clamping means comprise a circumferential series ofclamping plates which can be radially retracted and extended, for directengagement of the outer surfaces of the pipes. The division in clampingplates renders a better controllable clamping and aligning possible.

The initial placement is facilitated when the clamping means arearranged for a part of the circumference on a frame part which can beopened with respect to the rest of the frame, in which preferably thepart of the frame that can be opened takes up approximately 180 degreesor more of the circumference in circumferential direction. As a resultthe entire frame can be placed in radial direction around the pipes thatare to be welded together. Compared to the known line-up clamp that canbe moved within the pipes and the aforementioned known welding devicethat works with clamping sleeves, the advantage is obtained thatbringing the device to its destined place does not need much movementalong the first pipe.

Preferably the frame is provided with, preferably hydraulic, operatingmeans for moving the frame parts that can be opened.

In an advantageous manner the frame that is situated outside around thepipes can be used for an additional function, in that sense that theframe is furthermore provided with a wind shield for screening off thewelding area radially to the outside.

Preferably the frame is furthermore provided with a longitudinal shellor structure extending in pipe centre line, which preferably has acircumference of 180 degrees or less. Said structure or saidlongitudinal shell can be advantageous for the aligning and for themovement of the frame, as well as for the support of the parts for theoperation and drive of the parts of the device. It is advantageous herewhen the longitudinal shell or structure is provided with supporting orguidance rollers, which preferably in pipe centre line direction are inline with each other like several rollers.

The aligning and guidance is promoted when several sets of rollers arepresent which are spaced apart in circumferential direction.

Preferably the first and the second clamping means are arranged ondifferent frame parts, that are connected to each other by means ofconnection means that can be adjusted in axial direction, preferably(hydraulic) cylinders, in order to be able to adjust the position of theend edges to the desired position for the weld.

From a further aspect the device comprises means for operating the firstclamping means, means for determining an abutment position of the firstclamping means, means for storing the abutment position in a memory,means for operating the second clamping means, in which the means foroperating the second clamping means are connected to the control meansfor moving the second clamping means to a position corresponding to theabutment position, based on the abutment position as stored in thememory.

Preferably the means for operating the first clamping means and themeans for operating the second clamping means are adapted for urging theclamping means from the abutment position to a clamping position.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be elucidated below on the basis of an exemplaryembodiment shown in the attached drawing, in which:

FIG. 1 shows a view in perspective on a device according to theinvention, in a partly opened position;

FIG. 2 shows an end view on the device of FIG. 1, in another position;and

FIG. 3 shows a view in perspective on the device of FIG. 1, however fromanother side.

DETAILED DESCRIPTION

The aligning device 1 of the FIGS. 1 and 2 is used for aligning thepipes 2 and 3, which are situated with their end edges near each other.The pipes 2 and 3 are here supported by means that are not furthershown, the pipe 2 for instance on blocks or a mound of soil, the pipe 3hanging from a crane or also on a mound of soil. The part of the pipeline that is ready extends in the direction A.

The device 1 comprises a frame 100. The frame is substantially formed bytwo rings 101 and 102, in which clamping shoes 32 and 33, respectively,have been arranged in a radially extendable and retractable manner, inwhich in FIG. 1 the ends of the radially movable jacks 30 and 31,respectively, of the clamping shoes 32 and 33, respectively, can beseen.

The main parts of the rings 101 and 102 are semi-circular brackets 9 and10, which at their ends are hingedly connected to bracket segments 11,12 and 41, 51 by means of hinged joints 25, 26 and 42 (see FIG. 2: itwill be understood that the bracket 10 is designed substantiallyidentical to bracket 9). The bracket segments 11, 12 and 41, 51 aremoreover connected to the brackets 9 and 10 by means of hydrauliccylinder assemblies 13, 14, 15, 16, and namely by means of hingedattachments 19, 20, 43 on the brackets 9 and 10, hinged joints 21, 22and 44 on bracket segments 11, 12 and 41, 51 and cylinders 23, 24 and 45attached in between them. Bracket segment 51 corresponds to bracketsegment 41.

As can be seen in FIG. 2 the clamping shoes 32, 33 form series runningin circumferential direction.

The frame 100 is further provided with supports 17 and 18 extendingradially and axially from the brackets 9 and 10, which supports areconnected to each other by means of cylinders 52 a, 52 b in a rigid,though axially adjustable manner. In a comparable manner supports 36, 37and 34 and 35, respectively, extend from the bracket segments 11, 12 and41, 51, which supports are connected to each other by means of cylinders39 and 38 in the same manner as the supports 17 and 18.

Furthermore attached to the frame is a relatively long, semi-circlecylindrical shell 4 to the already part of the pipe line (which shell isshort enough, however, to be able to traverse the bends of the pipeline) and a relatively short funnel 5 extending around the pipe 3, whichfunnel for that matter is divided. The shell 4 can also be formed likean open structure, such as a lattice structure. The shell 4 can beprovided with running/supporting wheels 6, 7 and 8, with which thedevice 1 is supported on the pipes 2 and 3 and can be moved over it inthe direction B. In this case the wheels or rollers 6 and 8 can rotatefreely, to which end, as shown for the rollers/wheels 6 and 8,suspensions 27 and 29 have been provided. The rollers 7 are driven bymeans of a drive supported on the shell 4, which drive is not shown, andare bearing mounted in trestles 27. An active control can be providedfor the rollers 7. A roller can furthermore be coupled to aninclinometer. Finally the exemplary embodiment 1 shown, according to theinvention is provided with a bracket 50 which is attached to both theshell 4 and the frame and connects them to each other, from whichbracket the device can be suspended during its placement and removal andby means of which the device 1 can be pulled in the direction B. Apartfrom the bracket 50 no constructive connection is necessary between theshell 4 and the frame 100.

The bracket assemblies 9, 10, 11, 12, 41, 51 assembled in the manner ofFIG. 1, form as it were one frame and are moreover able to offer room towelding means, such as a guide for a welding robot extending incircumferential direction, the welding robot itself (see 80 in FIG. 3),gas supply means, wire supply means etc. Moreover the frame or shell 4can offer room to driving means for the cylinders 23, 24, 45 and so onand for the clamping shoes 32 and 33 that are provided on the bracketsand the bracket segments.

Furthermore a control and regulation unit (not shown) has been arrangedon the frame 100 or on the shell 4, with which unit the various partscan be operated and controlled. Said unit particularly comprises ameasuring device for determining the position of the clamping shoes 32and 33, in particular at abutment against the wall of the pipeconcerned, and storing said position in the memory.

When the pipes 2 and 3 have to be welded to each other with their ends,the device 1 is lowered on the bracket 50, until the wheels or rollers6, 7, 8 find support on the outer surfaces of the pipes 2 and 3, such asouter surface 2 a of pipe 2 (see FIG. 2). In this way the device 1 isalso somewhat centred with respect to the pipe 2. The pipe 3 is thenstill hanging from a crane. Subsequently the cylinders 23, 24, 45 areactivated to urge the bracket segments 11, 12, 41, 51, according torotation movements C and D, from the opened position into the closedposition, for bracket 11 shown in FIG. 2. Subsequently a tangentialcoupling is made with the help of couplings 53 a, 53 b between thesupports 34 and 36 that are near each other, and the same for the othersupports 35 and 37, so that an as it were continuous ring bracket iscreated. The funnel 5 here helps as orienting means for the pipe 3hanging from the crane, which after that can be supported by placing amound of soil under the pipe 3.

Subsequently the jacks 30 are operated to let the shoes 32 abut theouter surface of the pipe 2. Said position, which corresponds to thedegree of radial expansion of the jacks in question, is noticed by theaforementioned measuring device, and on the basis thereof a contoursketch is made and stored in a memory. Subsequently the jacks 30 aredriven to let the shoes 32 clamp the pipe 2.

The jacks 31 are then driven to bring the shoes 33 against the outersurface of the pipe 3 and subsequently move it to a positioncorresponding to the position as determined by the measuring device forthe corresponding shoes 32, in order to obtain an identical contoursketch, by deforming the wall of the pipe 3 where necessary. When thecontour of pipe 3 is already sufficiently of the same shape as pipe 2,adjustment of pipe 3 is of course unnecessary. The jacks 31 aresubsequently driven to let the shoes 33 clamp the pipe 3 entirely, sothat the pipes 2 and 3 are now both clamped and, as it were, form aunity with the frame 100 and as a result are fixed radially with respectto each other, in line with each other. It is noted that the jacks areadapted for generating sufficiently large clamping and deformationforces, such as for instance 3-4 tons.

Subsequently the hydraulic cylinders 38, 39, 52 a and 52 b are operatedto bring the end edges of the pipes 2 and 3 at the wanted distance fromeach other for making the weld. In case of a V-seam a little distance isnecessary, but in case of a J-seam not. When the wanted distance isreached the cylinders are fixed/secured in their expansion.

The aligning device 1 has been installed then and applying the weldedjoint can be started with the help of welding robot 80, which is movedin the circumferential direction E. With the device according to theinvention adjustment can take place with such precision that for weldingalso laser welding methods can be used.

It is advantageous when welding to weld the pipes 2 and 3 to each othersuch that they are connected to each other in a movement fixed manner,to move the device 1 to a next welded joint to be made and tosimultaneously finish the weld between pipes 2 and 3 with other weldingmeans.

When the pipe line in question is completed, the device 1 need not bemoved to a location where it can be driven from the last pipe, but thebracket segments can simply be opened again and the device 1 can behoisted away.

1. A device for welding a plurality of pipes together, said devicecomprising: (a) first and second rings, said first and second ringscomprising respective first and second clamping means for tightlyengaging outer sides of respective first and second pipes havingrespective ends in line with and at a welding distance from each other,each of said first and second rings being disposable in either (i) aclamping position with the first or second clamping means tightlyengaging outer sides of the respective first or second pipes or (ii) anon-clamping position with the first and second clamping means nottightly engaging the outer sides of the respective first or secondpipes, each of said first and second clamping means comprising aplurality of first and second clamping members, (b) support means forconnecting the first ring to the second ring to form a frame, saidsupport means extending axially and radially outward from respectiveouter surfaces of the first and second rings; (c) movement means on theframe for moving the frame along and over the plurality of pipes whilebeing supported on the pipes; and (d) welding means supported on theframe for welding the plurality of pipes, said welding means beingmovable along the frame in a circumferential direction, said first andsecond rings, connection means and movement means being assembled toallow such movement.